The woman says she had purchased the swimsuit at fashion retailer Glassons at a shopping centre across the road several months ago.
Now the woman has been the target of online trolls who have hit out at the swimmer.
"Guess we'd have to see the evidence, but looking at your profile, sounds like attention-seeking behaviour. Are you doing MAFS NZ next? Good luck", one troll said.
Another wrote: "Looks more like bra and knickers to me ... and you didn't get kicked out ... you decided to leave!"
Following the backlash, the woman has taken to social media to hit out at trolls.
She said she raised the incident online as a way to stand up for women who are objectified.
"Thank you for all of your support, it means more to me than you all know.
"In saying that, I am going silent for the next wee while. I am being inundated with trolls.
"This story wasn't supposed to be about me, it is about the injustice that was done regardless of who it was done to. Anyone who knows me personally knows that I rarely ever post anything on Facebook so this is pretty overwhelming for me.
"Oh, and I still haven't had this aforementioned apology from Auckland Council and I'm not expecting it to be honest. Much love to you all and anyone who has felt objectified and/or felt like they haven't had a voice, no matter what sex, race, or affiliation."
Head of active recreation at Auckland Council Rob McGee told Stuff that he was disappointed by the staff's actions.
"On behalf of the lifeguard who spoke to the customer and the team at Albany, I would like to offer a sincere apology to the customer," McGee said.
"We are sorry she was made to feel uncomfortable, and the lifeguard who passed on the feedback from other pool users now realises this wasn't the right thing to do.
"She was never asked to leave, however, we understand her decision."